The Concentric Zone Model: Explaining Urban Growth Patterns

How does a city decide where its banks go, where its immigrants settle, and where its wealthiest families build their homes? Long before urban planners had sophisticated data tools, sociologist Ernest W. Burgess proposed a remarkably systematic answer to this question. In 1925, he introduced the Concentric Zone Model – a framework that describes city growth as a series of rings expanding outward from a central core, each ring occupied by a distinct social and economic group. It was one of the first scientific attempts to map the social geography of an entire city, and it changed how sociologists, planners, and geographers think about urban life.

Origins of the model: the Chicago School and human ecology 🔗

The Concentric Zone Model did not emerge in isolation. It grew out of the intellectual tradition of the Chicago School of Sociology, which treated the city as a natural laboratory for understanding human behavior. Sociologists at the University of Chicago developed the concept of human ecology – the idea that cities, like natural ecosystems, are shaped by competition, adaptation, and the struggle of different groups for space and resources.

Burgess collaborated closely with Robert E. Park, who brought ecological thinking into sociology. Together, they observed that just as plants and animals compete for territory, social groups in cities compete for the most desirable land. Those who can pay the most occupy the most central, commercially valuable locations; those who cannot are pushed outward – or left in the least desirable zones. Burgess published his model in a 1925 chapter titled The Growth of the City: An Introduction to a Research Project, within the edited volume The City.

According to Burgess’s model, urban areas expand in rings, each characterized by a different type of land use and social activity, and this growth is driven by economic forces and social dynamics rather than chance.

The five concentric zones explained 🔗

The model divides the city into five distinct zones, each with its own land use pattern, population type, and socioeconomic character. Moving outward from the city’s core, the zones represent a gradient from maximum commercial density to low-density suburban living.

Zone I: the central business district (CBD) 🔗

At the very heart of the city sits the Central Business District. This is where economic and commercial life is most concentrated – banks, offices, government buildings, hotels, theaters, and retail establishments. The CBD is a zone of non-residential, commercial activities and is characterized by high property costs. Because it is the most accessible point in the city, land values here are the highest. Burgess’s work contributed to what later became known as the bid-rent theory – the idea that the amount businesses and individuals are willing to pay for land decreases as distance from the city center increases.

Zone II: the zone of transition 🔗

Immediately surrounding the CBD is arguably the most socially complex zone in the model. Zone II is composed of formerly wealthy homes split into cheap apartments for new immigrant populations; this zone also houses small manufacturers, pawn shops, and other marginal businesses. It is a zone in flux – old residential buildings deteriorate as commercial expansion encroaches from the center, while low-income and immigrant families move in because rents are affordable.

The zone of transition is also characterized by high levels of social disorganization – phenomena like delinquency, crime, and poverty tend to concentrate here, partly because the population is highly transient and social bonds are weak. Frederic Thrasher’s landmark 1927 study, which mapped over 1,300 gangs across Chicago, found their overwhelming concentration in precisely this transitional zone, aligning with Burgess’s predictions about ecological instability.

Zone III: the zone of working-class homes 🔗

The third ring is home to blue-collar workers and their families – people who have moved out of the zone of transition as their economic circumstances improved slightly, but who still need to live within reasonable distance of their workplaces. Burgess describes this working-class zone as close enough to the city center that workers can reach their workplaces on foot. Housing here consists of older single-family homes, row houses, and small apartment buildings. These are neighborhoods of stability – not affluent, but not in decline either. Many of the residents are second-generation immigrants who have graduated from the transitional zone.

Zone IV: the zone of better residences 🔗

Further out lies the residential zone for the middle and upper-middle classes. This zone is characterized by newer and more spacious homes for middle-class families who can afford daily transportation to the CBD. Properties here are detached, with yards, garages, and access to parks and upscale retail. Residents are typically well-educated, white-collar professionals who have the financial means to separate their homes from the noise, crowding, and industrial activity of the inner zones. The ability to commute – by rail or personal vehicle – is what makes this zone accessible.

Zone V: the commuter zone 🔗

The outermost ring is the commuter zone, encompassing suburbs and satellite towns located roughly 30-60 minutes from the CBD. This zone extends beyond the city limits and comprises suburban communities within commuting distance of the CBD, characterized by low-density housing. Residents here are typically the wealthiest, able to afford not only large homes but also the cost of daily commuting. Burgess himself noted that in the case of Chicago, settlement in this outer zone followed the lines of railroads radiating outward from the city center, rather than forming a perfect circle.

Invasion and succession: the engine of urban change 🔗

The Concentric Zone Model is not just a static map – it is a theory of process. Burgess argued that cities don’t simply grow by adding people; they grow through a dynamic mechanism he called invasion and succession, borrowed directly from plant ecology.

Invasion refers to the movement of a new group – typically immigrants or lower-income migrants – into an area already occupied by another group. Invasion is a process that necessitates continual expansion of inner zones into outer zones, driven by the natural pressure of migrants moving into the city. As the CBD grows commercially, for example, it “invades” the transitional zone, pushing residents outward.

Succession follows invasion. Once a new group establishes itself in a zone, it gradually displaces the previous inhabitants, who then move to the next outer ring. Burgess described this process using the image of a tidal wave – immigrant groups flooding into the inner zones and dislodging existing residents, who in turn overflow into the next zone outward, and so on. The result is a cascading chain of residential movement across all zones.

This cyclical process means that each zone is always being pressured by the zone immediately inside it. The transitional zone is under commercial pressure from the CBD; working-class neighborhoods feel the push of transitional-zone residents seeking to improve their conditions; and so on outward. Urban growth, in Burgess’s view, is fundamentally a social competition – not unlike ecological competition in the natural world.

Chicago as the case study 🔗

The model was built specifically around the city of Chicago in the 1920s, and for good reason. Chicago served as Burgess’s original model – he was a professor at the University of Chicago, which was part of the Chicago Regional Planning Association, attempting to map what was happening in this rapidly growing metropolis.

Early 20th-century Chicago was experiencing explosive growth driven by industrialization and massive waves of immigration from Europe and internal migration from the American South. Burgess illustrated how Chicago’s growth followed patterns of invasion and succession, with population density highest near the central business district and decreasing outward, while socioeconomic status and residential quality increased with distance from the center.

The Near North Side of Chicago, for instance, displayed stark zonal contrasts – transient, low-income populations near the center, giving way to more stable, wealthier communities further out. Gang activity, as Thrasher’s research showed, was clustered in the transition zone. Even Chicago’s physical geography – with Lake Michigan forming a natural boundary – meant that the model applied more as a series of concentric semicircles than full rings, a limitation Burgess himself acknowledged.

The model’s influence and legacy 🔗

Despite being nearly a century old, the Concentric Zone Model had a remarkable impact on urban sociology and planning. The model captured the imagination of sociologists, geographers, and planners as they tried to understand and manage what was happening in rapidly growing American cities. It directly inspired two subsequent models: Homer Hoyt’s Sector Model (1939), which argued that growth follows transportation corridors in wedge-shaped sectors rather than rings, and Harris and Ullman’s Multiple Nuclei Model (1945), which proposed that cities develop around several centers of activity rather than one.

The model also had real policy implications. In urban planning, the model provided early tools for predicting radial expansion and land-value gradients, informing zoning ordinances and infrastructure placement in growing American cities during the interwar period. Understanding where different populations were likely to settle helped planners anticipate where schools, transit lines, and public services would be needed.

Criticisms and limitations 🔗

The model has attracted substantial criticism over the decades, and many of those critiques are valid. The most fundamental is that it was derived from a single city – Chicago in a very specific historical moment – and its inapplicability to cities outside the United States is one of the most significant criticisms scholars have raised. In Paris, for example, the pattern is almost reversed: wealthy residents occupy the central arrondissements, while low-income populations live in the suburban periphery – the opposite of what Burgess described. Similarly, in cities like Rio de Janeiro, the poorest communities (favelas) occupy the high-elevation outskirts, not the transitional inner zones.

Even within the United States, the model oversimplifies. It assumes a flat, uniform terrain with transportation radiating equally in all directions – conditions that rarely exist. It also ignores the role of government intervention, zoning laws, and urban renewal policies, which can dramatically reshape the spatial distribution of social groups. The model neglects institutional interventions for the redevelopment of the CBD and the transition zone – today, many former transitional zones have been redeveloped into vibrant downtown districts with upscale restaurants, clubs, and commercial complexes.

Gentrification is perhaps the clearest modern challenge to the model’s logic. When wealthier residents move back into inner-city neighborhoods – reversing the outward flow Burgess described – the neat ring structure breaks down. Modern cities are also shaped by phenomena Burgess could not have anticipated: remote work, decentralized economic activity, and global capital flows that invest in downtown luxury housing while leaving surrounding areas underdeveloped.

That said, critics generally acknowledge that the model was never intended to be a perfect description of every city. Despite these limitations, the Concentric Zone Model played a significant role in shaping urban sociology and provided a foundation for further research and understanding of urban structure and processes. Burgess himself noted that no city – not even Chicago – fits the ideal scheme perfectly.

Why the model still matters 🔗

The Concentric Zone Model matters not because it accurately describes today’s cities in detail, but because it introduced a way of thinking about cities that remains foundational. It established that where people live is not random – it is structured by economic competition, social pressure, and historical migration patterns. It showed that cities are dynamic systems, constantly being reorganized by the push and pull of different groups. And it opened the door to a century of empirical urban research that continues to examine how social inequality, ethnicity, and class shape the spatial organization of urban life.

Contemporary research on Chicago’s spatial patterns still finds echoes of the concentric model – minority neighborhoods concentrated near the urban core, wealthier populations in the outer suburbs – though the picture is now far more complex, with growing zones of diversity that cut across the old boundaries Burgess mapped.

What do you think? Does the logic of invasion and succession – where one social group gradually displaces another due to economic pressures – still apply to neighborhoods in cities today? And if wealthier residents are now moving back into city centers through gentrification, does that mean urban growth is reversing the pattern Burgess described, or simply adding a new layer to it?

References

1. https://www.britannica.com/biography/Ernest-Watson-Burgess
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3. https://www.dustinstoltz.com/blog/2015/12/02/burgess-concentric-zone-model-of-urban-development/
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